03/1989 E24 635csi Rough idle & warm start issue

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bm635csi
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03/1989 E24 635csi Rough idle & warm start issue

Post by bm635csi »

Something I found when Investigating Rough idle & Misfire & warm start issue.

Engine stalls when under load when at full operating temp and struggles to start when its warm. When engine cools down, it not longer misfires , smooth idle and not issue starting.

Did the usual as below

- Removed and Clean ICV with throttle body cleaner. Yes lots of crap came out.
- Fitted and its a lot better at idle but still have misfire when at operating temperature.
- Struggles under load when engine reaches operating temperature.
- Its is pointing to something Electrical/ignition as it misfire when everything is hot and under load

Update ( 11/6/2022 )
Found corroded Air temperature sensor terminal on Airflow meter. When temperature comes up to normal and stays hot , resistance goes out of spec and produces reading of negative (-14c )hence the MAF flap shuts and dumps fuel and stalls the engine ..Fixed the corroded terminal and all is good now

link to video after the fix .
https://youtu.be/tlsjNwb8Lzs

link to video before the fix
https://youtu.be/tr7QbIpwjUc
https://youtu.be/Br6O_poWoUA

Another area to look at when troubleshooting rough Idle issue
///bm635csi
1989 E24 635CSi Highline
2003 E46 M3 SMG
2002 L322 Range Rover Vogue
1991 E34 535is
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